Metal pipe, such as drill pipe, is normally assembled by joining adjacent lengths of drill pipe. The ends of the drill pipe are normally upset for welding to a threaded tool joint for connection of adjacent pipe lengths. The drill pipe lengths prior to forming of the upset ends and threads are of a constant wall thickness and have uniform inner and outer peripheries. A conventional method of forming an upset utilizes a die mandrel to form in a forging operation an external upset portion of increased wall thickness. Then, in a separate step with another die and mandrel, the end of the pipe is pressed or squeezed inwardly to form an internal upset portion. As used herein, the term “tubular” refers to green tubes, upsetted tubes, drill pipe, threaded casing, threaded tubing and tool joints.
Conventionally, it is important to be able to control the inventory of such pipe during the formation of the upset and subsequent to the formation of the upset. Whenever “green pipe” is received and throughout the upsetting operation, a bar code is applied to the outer diameter of this green pipe. The pipe is identified and orientation numbered by applying a bar code for traceability purposes. This bar code is applied with either paint or by the application of a label onto the outer diameter of the pipe. Such a bar code can correspond to heat, lot, purchase order number and pipe description. Once this bar code is applied to the outer diameter of the pipe, the information regarding the pipe can be stored in the computer system of the upsetting factory. As such, inventory control can be effectively maintained by the factory. A particular length of tubular can be continually monitored throughout the manufacturing process.
Unfortunately, in the manufacturing of present tubular products or other related steel products, it is impossible to paint a barcode and numbers with paint that is able withstand the severe thermal shock at the heat treatment portion of the manufacturing processes. The heat treatment process during the manufacture of the tubular will encounter temperatures as high as 1800° F. This tubular is then water-quenched with up to 300 p.s.i. of water pressure or severe oil quenched. Such heat treatment and quenching activities are carried out in order for the tubular, or other related products, to reach the proper physical properties for usage. At present, nearly all tubular products that go to heat treatment are hand-stamped at one end by several employees. This often develops a problem in that numbers are not stamped correctly. As a result, there is a loss of traceability. This can create problems for inventory control, customers, tracking, traceability, accounting, loss of production and for the waste of man-hours in correcting these problems.
It is an object of the present invention to provide a method of marking a tubular that increases the ability to trace the tubular during the manufacturing process.
It is another object of the present invention to provide a method of marking a tubular which improves the efficiency of the manufacturing process.
It is a further object of the present invention to provide a method of marking a tubular that enhances inventory control in the manufacturing environment.
It is another object of the present invention to provide a method of marking a tubular that reduces costs associated with the marking of the tubular and enhances the profitability associated with the sale of such manufactured tubular.
It is another object of the present invention to provide a method of marking a tubular which reduces human error.
It is a further object of the present invention to provide a method of marking a tubular that enhances the productivity associated with the manufacture of the tubular.
It is another object of the present invention to provide a method of marking a tubular that allows for instant data collection during the manufacturing process.
It is still another object of the present invention to provide a method of marking a tubular that enhances the ability to accurately cost the labor associated with the manufacture of the tubular.
It is another object of the present invention to provide a method of marking a tubular that is relatively easy to implement.
It is another object of the present invention to provide a method of having a barcode marked on tool joint 35° that will have all information of manufacturing process and description of both tool joint and tubular product all transferred by computer network.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.